I was wondering if any one knows the internal measurements of one of the 10 gallon rubbermaid coolers(the big orange ones). i have tried to input the measurements that i was able to find but for some reason they do not work out in the calibration tab. Upon entering the measurements i keep getting the wrong capacity, it should equal 10 gallons but it keeps coming out to be like 20 gallons. Can anyone give help me out or give me some insight into this problem?